Prior control systems have included in-line hydraulic controls for regulating the speed of a shot cylinder of a die casting machine. The valve components of such systems are susceptible to dirt particles. They require a flow sensor in the hydraulic line to sense the hydraulic flow that drives the hydraulic shoot ram and a feedback signal of variations in the in-line hydraulic flow is sensed for regulating ram speed. Periodic maintenance of such hydraulic systems is more involved because of the presence of such complex control components in the hydraulic flow stream.
Other controllers have included a position transducer located inside the cylinder of a hydraulic shot cylinder to control the position of the ram for a slow shot or a fast shot. Such controllers do not include velocity feedback functions to compensate for changes of operating variables which result from changes in the fluid mechanics of the system.